This HOWTO describes one way to do a Netboot install of Ubuntu by booting from files on a hard disk. This installation method does not require burning a CD (or using any other external media, like a USB key), and it does not require you to configure a server on your LAN for PXE booting.

You need to have grub or grub2 already installed and bootable in order to use this method. It is therefore suitable for installing Ubuntu over an existing GNU/Linux installation.

Alternatives

If the computer you are installing on does not have network connectivity during installation, consider using the Installation/FromLinux method, which involves retrieving packages from an ISO instead of from the Internet at installation time.

Instructions

If the computer you wish to boot is not the same as the one you have grub installed on, then make a disk have a single megabyte free space (for the boot loader) followed by a small partition (to store the appropriate ramdisk image and kernel on). Mount this disk in the computer with grub, then (at least for older hardware and) do

Save them somewhere that grub can read from. Inside /boot is a fine place. (These files are quite small, under 10MB for either architecture.)

3. Reboot your computer and press ESC if necessary to enter the grub menu (press Shift if you use grub2). Now we will get grub to boot from the files you just downloaded.

Press c to get a grub command prompt. Type each of the following lines:

root=(hd0,1)

Replace the root partition with the drive and partition on which your /boot is located. You can look at and copy the root line of any existing boot menu entry if you are at all unsure what this is, or you can try tab-completing after root ( or root (hd0,.

In Grub2, the default for Ubuntu 10.04 LTS and onwards

linux /boot/path/to/linux

Or in older versions of Ubuntu or where you have replaced it with Grub 0.97 (or there-abouts)

kernel /boot/path/to/linux

initrd /boot/path/to/initrd.gz

Replace these paths with the actual paths where you saved the files. If you saved them directly in /boot, the paths will be simply kernel /boot/linux and initrd /boot/initrd.gz.

boot

Your system should now boot into the Ubuntu installer. Follow the instructions from there.